speedo calibration

[Telford Transit]

Hoping one of the ford techs can tell me if the speedo in a 2005 2.4 can be re-calibrated?

I have converted a 135 tdci to a 90ps tddi but kept the 6 speed box/axle and the speedo is miles out

cheers

[taz666]

if its got the same gearbox and axle then should be the same and if its got abs the speed is sourced through the abs

[darkbluevanman]

As above?... maybe it was out before, maybe it's got lazy.... probably a trim in the clocks to adjust the reading... all speedo's read fast!

[Telford Transit]

Speedo reads through abs?? Not on a 2005, it reads from the speedo sensor on the gearbox

speedo usually reads high but not 85mph whilst doing 20mph

its running the six speed tdci box through the tddi loom/ecu

speedo needs calibrating much the same way as a tachograph would be calibrated when installed
just need to know if that is possible,cant get a straight answer out of main dealer

[Altransit]

MartynX (Vantuner) may be able to help, give him a ring

[martynx]

With such a big difference you either have a very different feed signal from the new set ups speed sensor going into the new 90 ECU or the rev counter in the clocks differs.. only way i can think of of testing whats causing it is measure a 135's speed signal from the gearbox & compare it with a 90's one... on older tddi clocks you can swap in other rev counters very easily, not sure on your digi dash model though if thats poss

Theres no gross calibration option in the ECU , like selecting 90/100/135ps etc but you can fine tune by changing specified diff ratio or tyre size....

[Boler90]

Hi old post but was this problem ever sold iv just bought a 2006 mk6 125 bhp wich somebody has fitted a 135 6 speed gearbox to and I'm having exact same problem speedo reads around 100 mph when actual speed is about 30 mph

[martynx]

Hi old post but was this problem ever sold iv just bought a 2006 mk6 125 bhp wich somebody has fitted a 135 6 speed gearbox to and I'm having exact same problem speedo reads around 100 mph when actual speed is about 30 mph

What is the reg number ?

[martynx]

I know where the calculation factors are in TDDI ecu' s so it may be poss to adjust such a massive difference, need to try to see if it will accept it,

Sent from my SM-G900F using Tapatalk

[ake]

If the van has abs, unplug the gearbox sensor, it's been on here before, and that fixed it!

[Boler90]

Hi thanks iv just been out and unplugged the sensor this results in the speedo not working at all..
Anything else I could try

[GeeJayent]

Hi all, any updates on this fault?

I have just had a 6 speed box conversion done on 125 tddi 2005 and speedo is reading about 3 times what it ought to.

I don't think abs is fitted but will find out today hopefully

Box came from a 135 tdci engine. Not sure if that makes a difference

Thanks

[martynx]

- The gearbox speed sensor goes to the engine ECU, then there is some calculation then the signal goes to the clocks & if alls well the speedo reads about right albeit + a few % for legal reasons. I think the calculation involves axle ratio,tyre size, & number of teeth of gearbox sensor wheel. The number of teeth bit is a guess based on Euro 5 Transits definitely having a setting for number of teeth. I have documentation for Euro 4 & 5 ECU's but nothing exists for the euro 3 so i for one don't where the number of teeth setting is.

I have tried different tyres sixes & axle ratios including up to 20:1 & 25:1 & the speedo readings are out still then the speedo cuts out or worse the engine loses power.

As far as i know (as i did my mods by post), the above results were achieved using a TDDI speed sensor, as the number of wires & plug differs from TDCI to TDDI . one has 2 & one has 3 wires.

There's no option to use a different engine ECU as they are totally different.

Maybe someone who makes gadgets for japanese import cars could make something for the speedo itself , or just someone who understands how they work could put a resistor or something in the right place.